79 converters · 9 categories
Free Online Unit Converter
Free Online Unit Converter
for Every Measurement
Instantly convert length, weight, temperature, volume, area, speed, energy, and 79+ other unit types. Accurate to 12 decimal places — no ads, no signup, no tracking.
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Length conversions — open any other for the full experience.
1 m = 3.28084 ft
Popular conversions
One-click links to the most-used conversions.
cm to inches inches to cm mm to inches inches to mm meters to feet feet to meters km to miles miles to km cm to feet feet to cm inches to feet feet to inches meters to yards yards to meters kg to lbs lbs to kg grams to ounces ounces to grams pounds to ounces ounces to pounds Celsius to Fahrenheit Fahrenheit to Celsius liters to gallons gallons to liters mL to cups cups to mL mph to kph kph to mph acres to square feet square feet to acres radians to degrees degrees to radians hp to kW kW to hp
All converters
Browse the full catalog by category.
Common
18 converters Length Convert between metric and imperial length units: meters, feet, inches, miles, and more. Weight and Mass Convert between mass units: kilograms, pounds, ounces, tons, and more. Volume Convert between liters, gallons, cups, milliliters, and other volume units. Temperature Convert between Celsius, Fahrenheit, Kelvin, Rankine, and Reaumur. Area Convert between square meters, square feet, acres, hectares, and more. Pressure Convert between pascals, bars, atmospheres, psi, and more. Energy Convert between joules, calories, BTUs, kilowatt-hours, and more. Speed Convert between mph, kph, knots, m/s, and more. Time Convert between seconds, minutes, hours, days, years, and more. Power Convert between watts, horsepower, kilowatts, BTU/h, and more. Force Convert between newtons, pound-force, dynes, and other force units. Angle Convert between degrees, radians, gradians, arc minutes, and seconds. Fuel Consumption Convert between L/100km, MPG (US/UK), km/L, and more. Numbers Convert numbers between decimal, binary, octal, and hexadecimal. Case Convert text case: UPPER, lower, Title, camelCase, snake_case, kebab-case. Data Storage Convert between bits, bytes, MB, GB, MiB, GiB, and more. Volume — Dry Convert between dry-volume units like dry pints, dry quarts, pecks, and bushels. Currency Live currency conversion is coming soon. We are evaluating providers — bookmark this page!
Engineering
8 converters Angular Velocity Convert between rad/s, deg/s, RPM, and revolutions per second. Acceleration Convert between m/s², ft/s², g, and other acceleration units. Angular Acceleration Convert between rad/s², deg/s², and revolution-based accelerations. Density Convert between kg/m³, g/cm³, lb/ft³, and other density units. Specific Volume Convert between m³/kg, L/kg, ft³/lb, and other specific volume units. Moment of Inertia Convert between kg·m², lb·ft², and other moment of inertia units. Moment of Force Convert between N·m, lb·ft, and other moment of force units. Torque Convert torque between N·m, lb·ft, lb·in, and other units.
Heat
10 converters Fuel Efficiency — Mass Convert energy-per-mass: J/kg, BTU/lb, kJ/kg. Fuel Efficiency — Volume Convert energy-per-volume: J/m³, BTU/ft³, therm/gal. Temperature Interval Convert temperature differences (intervals) between scales. Thermal Expansion Convert thermal expansion coefficients between 1/K, 1/°C, 1/°F. Thermal Resistance Convert thermal resistance: K/W, °F·h/BTU. Thermal Conductivity Convert thermal conductivity: W/(m·K), BTU/(h·ft·°F). Specific Heat Capacity Convert specific heat capacity: J/(kg·K), BTU/(lb·°F). Heat Density Convert heat density: J/m², BTU/ft², cal/cm². Heat Flux Density Convert heat flux density: W/m², BTU/(h·ft²). Heat Transfer Coefficient Convert heat transfer coefficient: W/(m²·K), BTU/(h·ft²·°F).
Fluids
10 converters Flow Convert volumetric flow: m³/s, L/min, gal/min, ft³/h. Flow — Mass Convert mass flow: kg/s, kg/h, lb/min, lb/h. Flow — Molar Convert molar flow: mol/s, kmol/h, mmol/s. Mass Flux Density Convert mass flux density: kg/(s·m²), g/(s·cm²), lb/(h·ft²). Concentration — Molar Convert molar concentration: mol/m³, mol/L, mmol/L. Concentration — Solution Convert solution concentrations: g/L, mg/L, kg/L. Viscosity — Dynamic Convert dynamic viscosity: Pa·s, poise, centipoise. Viscosity — Kinematic Convert kinematic viscosity: m²/s, stokes, centistokes. Surface Tension Convert surface tension: N/m, dyne/cm, mN/m. Permeability Convert permeability: kg/(Pa·s·m²), perm.
Light
5 converters Luminance Convert luminance: cd/m², stilb, foot-lambert, nit. Luminous Intensity Convert luminous intensity: candela, candlepower. Illumination Convert illuminance: lux, foot-candle, phot. Digital Image Resolution Convert image resolution: DPI, dot/cm, dot/m. Frequency Wavelength Convert between frequency (Hz) and wavelength (m, nm) via λ = c/f.
Electricity
15 converters Charge Convert electric charge: coulomb, ampere-hour, faraday. Linear Charge Density Convert linear charge density: C/m, C/cm, C/in. Surface Charge Density Convert surface charge density: C/m², C/cm², C/in². Volume Charge Density Convert volume charge density: C/m³, C/cm³. Current Convert electric current: ampere, milliampere, microampere. Linear Current Density Convert linear current density: A/m, A/cm, A/in. Surface Current Density Convert surface current density: A/m², A/cm². Electric Field Strength Convert electric field strength: V/m, V/cm, V/in. Electric Potential Convert electric potential: volt, millivolt, kilovolt. Electric Resistance Convert resistance: ohm, kilohm, megohm. Electric Resistivity Convert electric resistivity: Ω·m, Ω·cm. Electric Conductance Convert conductance: siemens, mho. Electric Conductivity Convert conductivity: S/m, S/cm. Capacitance Convert capacitance: farad, microfarad, picofarad. Inductance Convert inductance: henry, millihenry, microhenry.
Magnetism
4 convertersRadiology
4 convertersOther
5 converters SI Prefixes Convert between SI prefix multipliers: kilo, mega, giga, tera, milli, micro, etc. Data Transfer Convert data rates: Mbps, MB/s, Gbps. Sound Convert sound and signal levels: bel, decibel, neper. Typography Convert typography units: pixel, point, pica, em. Volume — Lumber Convert lumber volume: board feet, cord, m³.
About unit conversion
A unit is a measurement of a quantity that is defined or adopted by tradition or law. The global standard is the International System of Units (SI), a modern form of the metric system, but other systems — imperial, US customary, CGS — remain in active use across science, engineering, and everyday life. Swippe bridges them with precise, reversible conversions.